介词短语补语 the prepositional phrase as a complement
The preposition “于” is often used in written language. It means “in”, “on” , or “at”. The prepositional phrase “于+TW” indicating time is used as an adverbial modifier before a verb, for example,
王教授于九月十号到北京。
When the prepositional phrase “于+TW\PW” is used after a verb or an adjective, it functions as a complement indicating time, location, or a certain aspect. This kind of complement is mostly used in written language, for example,
鲁迅生于1881年。
这种水果产于海南岛。
马大为毕业于ABC商学院。
他从早到晚忙于工作，家务事一点儿也不管。